The development of low cost, naturally sustainable, and high-performance electrode materials is the primary issue that determines the large-scale application of capacitive deionization (CDI). In this work, the nitrogen-doped activated porous carbon decorated by 3D interconnected graphene (NAPC/G) was synthesized by pre-carbonization and KOH activation of soy milk and graphene oxide composite gel (graphene tofu). The NAPC has an ultra-high specific surface area (SSA) of 2993.5 m² g⁻¹, rich micro-mesoporous structure, and good hydrophilicity. In addition, the 3D graphene network enhances the conductivity of the composite. Therefore, benefited from the synergetic effect of abundant ions adsorption sites and improved conductivity, the specific capacitance of NAPC/G electrodes is up to 370 F g⁻¹ and maintains capacitance retention of 97% after 3000 cycles. For CDI electrode materials, the salt adsorption capacity (SAC), desalination rate, and cycle stability are the three important parameters. In this work, the NAPC/G electrode achieves an high SAC of 38.5 mg g⁻¹, large desalination rate of 6.6 mg g⁻¹ min⁻¹ and good cycle stability that desalination performance remains 93.5% after 50 cycles. This research provides an effective way to promote the sustainable large-scale application of CDI.

开发低成本、自然可持续、高性能的电极材料是决定电容去离子（CDI）大规模应用的首要问题。在这项工作中，通过豆浆和氧化石墨烯复合凝胶（石墨烯豆腐）的预碳化和 KOH 活化合成了由 3D 互连石墨烯装饰的氮掺杂活性炭（NAPC/G）。NAPC 的超高比表面积 (SSA) 为 2993.5 m ²  g ^-1，丰富的微介孔结构，良好的亲水性。此外，3D 石墨烯网络增强了复合材料的导电性。因此，受益于丰富的离子吸附位点和电导率提高的协同效应，NAPC/G电极的比电容高达370 F g ^-1并在3000次循环后保持97%的电容保持率。对于 CDI 电极材料，盐吸附容量 (SAC)、脱盐率和循环稳定性是三个重要参数。在这项工作中，NAPC/G 电极实现了 38.5 mg g ^-1的高 SAC ，6.6 mg g ^-1  min ^{-1 的}大脱盐率循环稳定性好，50次循环后脱盐性能保持93.5%。该研究为促进CDI的可持续大规模应用提供了有效途径。